Fountain pen



o.l MITCHELL. FOUNTAIN PEN. APPLICATION FVILED SEPT- 23, 1921;

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Patented May 16, i922.

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OLIVER MITCHELL, 0F BROOKLINE, MASSACHUSETTS.

FOUNTAIN' PEN.

T 0 all whom t may concern.'

Be ity known that I, OLIVER MITCHELL, a citizenI of the United States, residing at Brookline, in the county of Norfolk and State of Massachusetts, have invented certain new, and useful Improvements in Fountain Pens, of which the following is a specification.

My invention is an improvement in fountain pens and consists in the provision at the rear of the fountain or barrel of such a pen, of a means for withdrawing air from the barrel to a: compartment at the upper end of the barrel,'thus rarifying the air in the barrel and causing an inflow of ink at the forward end of the barrel by the outer atmospheric pressure and later discharging the air from the upper compartment through a pipe leading from the upper compartment to the pen end of the barrel. rIhis operation isrepeated as often as may be necessary to empty the barrel of air and lill the barrel with ink.

In the drawings:

Figure l is a longitudinal sectional elevation, broken, of a fountain p en embodying` my imp-rovement, showing the interior parts as at the end of the air expelling stroke;

Figure 2 is a. partial longitudinal elevation, partly in section, showing the interiorI parts at the end of the air-rarifying stroke;

lFigure 3 is a cross-sectional view on line 3--3 of Figure l;

Figure 4 is a cross sectional view on line 4 4 o-f Figure l;

Figure 5 is a cross sectional view on line 5 5 of Figure 1 Figure 6 is a longitudinal elevation, partly in section, of a modification. l

'Ihe mechanism of my improved pen is of, the simplest. The fountain l carries at one end the feed bar 2 having ink feeding iissures 3 and a pen point 4:, as is usual. rlhe ink feed bar has, in addition to the ink ssures 3 another passage 5, which at its inner end is central of the bar and fountain, that is, corresponds with the longitudinal axis of the fountain and is connected with a pipe A extending axially of the fountain to nearl the top' or rear end of the same.

Slidably tting at the rear upper end of the fountain is a cupv or chamber B, and

Specification of Letters Patent. Patented May 16" 19221 Application filed September 23, 1921. Serial No. 502,616.

within this chamber and frictionally engaging the same, is a disk C' which is mounted upon the ipe A and has preferably slight capacity 'or motion to and fro along that pipe, between stops a, a. A packing c at end of the cup a gland b to compress a packing) between the cup and the fountain. referably on the interior surface of cup B, I provide a slot or slots E and also a stop or stops, e, so placed as to engage the disk C when the slots are opposite the edge of disk C, the length of the slots being such as just to provide an air passage orpassagesl around the disk C from one side to the other of the disk. f

Through the upper end of pipe A just heneath the cap or stop, a, are preferably formed one or more holes a2 communicating with the interior of pipe A.

The preferred operation is as follows:

The parts being assembled as shown in Figure l, to fill the pen, the pen end of the fountain is submerged in ink. The operator holding the fountain with one hand, grasps the plug Z2, which serves as a finger'ppiece at the outer end of cup B, with the other hand and draws the cup outward. The first effect of this action is to shift the disk C upward, on pipe A, by the frictional engagement of disk C and cup B, thus closing the holes a2 in pipe A (see Fig. 2)'. The cap or stop, a, limits the upward movement of disk C and continued movement of cup B enlarges the space above disk C, while disk C prevents air from passing from fountain l to relieve the partial vacuum thus formed, and also air.

The continued withdrawal of cup B con tinues, the air becoming more and more rarified, until slots E open a passage around disk C, stops e engaging disk C at this time andi prevlegnting further movement outwardly of cu i grs soon as slots E permit it, air from the fountain 1 passes by the disk C to the cup B, thus producing a sudden rarification ofl air yin the fountain 1 and causing atmospheric pressure tofbecome suddenly effective to force ink through fissures 3.

The cup B is now pushed inward. The first effect of this action is to shift the disk C downward, on pipe A, by the frictional engagement of disk C and cup B, thus opening the holes a2 in pipe A (see F ig. 1). r1`he stop a limits the downward movement of disk C and movement of cup B also pushes the slots E belowfthe edge of disk C thus closing the passages for air around the edge of lthe disk through slots E, which were opened'upon the up stroke of cup B and simultaneously diminishing the space above diskC, forcing the air in cup B through holes 0:2, pipe A and passage 5, to the outer These operations are repeated until the fountain is filled with ink, which will be indicated to the operator by the gradual decrease of ejected air bubbles at the immersed end of the fountain. W hen the bubbles begin to diminish the operation of the cup B should immediately cease.

It will be obvious that in filling a fountain pen through the pen end,`by atmospheric pressure, Athere are two conflicting conditions. lt is desirable that the ink passages should be relatively large in order that ink may flow inward through the ink passages freely and easily; it is also desirable that the ink passages should be only of capillary size, in order that as the fountain gradually empties, ink may not flow out through the ink passages by gravity or fiood 1n my improved pen l reconcile these conflicting requirements. My ink passages are .fissures of capillary dimension easily retaining ink, against gravity. but, in filling, by applying an accumulated suction tension suddenly l am enabled to force ink freely through the ink fissures. f

The rarification of the air at each stroke will be governed by the position of the grooves governing the passage of air from the fountain to the suction chamber. ff, for example, the grooves were near the lower end of the cup, the stroke would be longer, the rarification within the c up greater and the sudden rarification in the fountain greater when connection was made through the slots between cup and fountain, the result being a sudden and maximum application of atmospheric pressure to force ink into the barrel. It is obvious that, within limits, this ink moving air pressure may be governed as desired by providing for a desired length of movement by the cup.

l have shown and described the preferred .form of my device and have described above, the preferred `mode of operation. I do not, liowe ver, limit myself to this preferred form or `mode of operation, as, by simply leaving the upper end of pipe A. open at all times, upon the outward. stroke of cup B, ink will be drawn through pipe A above disk C and will flow through slots E into the fountain. Nhen this mode of operation is desired the disk C need have no movement upon pipe A and the upper end of pipe A is permanently open. This arrangement is shown in Figure 6.

. lf have shown and described grooves E upon the inner surface of the cup B, through which at the proper moment, communication is established between the fountain 1 and the interior of the cup B, above the disk C. .l am aware that the necessary passage for air around the disk C, can be established by apertures or constructions other than the specific grooves E, which l have shown and described and I intend to cover such'apertures or constructions by the use of the word grooves, the gist of the matter being that at the proper moment, movement of the cup establishes communication aroundor outside the disk from one side of the disk to the other side.

l claim:

l. ln a fountainpen, the combination of a fountain; a cup slidably mounted in the rear end of the fountain and having suitable grooves opening inwardly; a pipe longitudinally mounted within the fountain, open at its front end to the air, andv at its rear end communicating with the interior of the cup above a disk; that disk, mounted upon the pipe at its rear end, within the cup in frictional, air-tight engagement .at its edges with the inner walls of the cup.

2. ln a fountain pen, the combination of a fountain; a cup slidably mounted inthe rear end of the fountain and having suitable grooves upon its inner surface; a pipe longitudinally mounted within the fountain, open at its front end to the air and at its rear end communicating- .with the interior of the cup above a disk; that disk, mounted for longitudinal movement upon the pipe at its rear end, within the cup and in frictional, air-tight engagement at its edges with the inner walls of the cup, the disk moving to close the rear end of the pipe upon rearward movement of the cup and moving to open the rear end of the pipe upon forward movement of the cup.

3. ln a fountainpen, the combination'of a fountain, a cup slidably mounted in the rear end of' the fountain and having suit- CIK able grooves upon its inner surface; a pipe longitudinally mounted Within the fountain, open at its frontend to the air and at its rear end closed by a cap-stop and vented to the interior of the cup by a side aperture; a disk mounted for limited longitudinal movement upon the pipe at its rear end, within the oup and in frietional, air-tight 

